The present application claims priority under 35 U.S.C. xc2xa7119 of Japanese Patent Application Nos. 2001-371665 filed on Dec. 5, 2001, and 2001-303018 filed on Sep. 28, 2001, the disclosures of which are expressly incorporated by reference herein in their entireties.
1. Field of the Invention
The present invention relates to a four-cycle engine control device mounted in a vehicle such as a motorcycle, snow vehicle, or aquatic motorcycle.
2. Description of the Related Art
Conventionally, an oil pressure warning lamp driver circuit 1 of the kind shown in FIG. 13 is connected to a four cycle engine mounted in a snow vehicle, for example.
This oil pressure warning lamp driver circuit 1 includes an oil pressure switch 2 which is turned OFF when the pressure of lubricating oil circulating within the engine body (not shown) is higher than a reference pressure and turned ON when this pressure is lower than the reference pressure, and an oil pressure warning lamp 3 which is lit when the oil pressure switch 2 is ON and turns OFF when the oil pressure switch 2 is OFF. Further, an ignition switch 4 is connected to this circuit 1.
In this circuit 1, when the lubricating oil pressure is higher than the reference pressure and the oil pressure switch 2 is therefore OFF, the oil pressure warning lamp 3 remains OFF even if the ignition switch 4 is turned ON.
On the other hand, when the lubricating oil pressure is lower than the reference pressure and the oil pressure switch 2 is accordingly ON, the oil pressure warning lamp 3 is lit as a result of the ignition switch 4 being turned ON. The user is made aware of the fact that the lubricating oil pressure is abnormally low upon seeing that the oil pressure warning lamp 3 is lit, and then manually performs a protection operation such as stopping rotation of the engine or reducing the engine speed.
However, in cases where the user continues to travel having failed to notice lighting of the oil pressure warning lamp 3, problems are readily produced such as abnormal wear of bearings, e.g., such as those used for the piston rings, crankshaft, camshaft and so forth, reduced engine durability, and scorching of engine parts.
Furthermore, with a conventional structure in which the above-mentioned oil pressure switch 2 alone is provided, there is the drawback that when an apparent drop in lubricating oil pressure is attributable to failure of the above-mentioned oil pressure sensor, the engine is then stopped urgently even if a lubricating oil pressure drop has not actually occurred.
Accordingly, one object of the present invention is to provide a vehicle-mounted four cycle engine control device whereby the engine can be suitably protected while avoiding a disabling of travel as a result of failure of the oil pressure switch.
In order to achieve the above object, the present invention may have the following arrangement.
That is, the present invention includes an oil pressure detecting sensor for detecting the pressure of lubricating oil circulated under pressure in an engine body. An oil pressure detecting sensor failure judging system or arrangement is provided for judging whether or not the oil pressure detecting sensor has failed. An engine speed judging system or arrangement is provided for judging whether or not the speed of the engine is equal to or above a predetermined engine speed. A pressure state judging system or arrangement is provided for judging whether or not the lubricating oil pressure detected by the oil pressure detecting sensor continues to be in a state of being lower than a predetermined reference pressure for a predetermined time interval or more. An engine control system or arrangement is provided for immediately stopping drive of the engine or reducing the rotation of the engine to a preset engine speed when it is respectively judged by each of the judging systems or arrangements that the oil pressure detecting sensor has not failed, that the engine speed is equal to or above the predetermined engine speed and that the lubricating oil pressure continues to be in a state of being lower than the reference pressure for a predetermined delay time or more.
The action of a vehicle mounted four cycle engine control device of the arrangement described above is as below.
That is, it is judged whether or not the oil pressure detecting sensor has failed, whether or not the engine speed is equal to or above the predetermined engine speed, and whether or not the lubricating oil pressure continues to be in a state of being lower than the reference pressure for a predetermined delay time or more, respectively, and when the judgment results are that the oil pressure detecting sensor has not failed, that the engine speed is equal to or above the predetermined engine speed and that the lubricating oil pressure continues to be in a state of being lower than the reference pressure for the predetermined delay time or more respectively, the engine speed is reduced.
It is thus possible to suitably protect the engine by distinguishing a lubricating oil pressure reduction which necessitates an engine speed reduction including engine drive stoppage.
The oil pressure detecting sensor failure judging system operates according to whether or not the oil pressure detecting sensor detects that the lubricating oil pressure is higher than the reference pressure within a required failure judgment time interval after the engine is started and a complete combustion mode has been assumed, whereby it is possible to avoid a malfunction such as that of halting rotation of the engine when the oil pressure detecting sensor fails.
The present invention may also include a rollover detecting sensor for detecting vehicle rollover, a rollover judging system or arrangement for judging whether or not a vehicle rollover state continues for or exceeds a predetermined time interval, and an engine control system or arrangement for immediately stopping drive of the engine or reducing the rotation of the engine to a preset engine speed when it is judged by the rollover judging system that a vehicle rollover state continues for or exceeds the predetermined time interval.
Furthermore, the present invention may also include an oil pressure detecting sensor for detecting the pressure of lubricating oil circulated under pressure in an engine body. An oil pressure detecting sensor failure judging system or arrangement is provided for judging whether or not the oil pressure detecting sensor has failed. An engine speed judging system or arrangement is provided for judging whether or not the speed of the engine is equal to or above a predetermined engine speed. A pressure state judging system or arrangement is provided for judging whether or not the lubricating oil pressure detected by the oil pressure detecting sensor continues to be in a state of being lower than a predetermined reference pressure for a predetermined time interval or more. A rollover detecting sensor is utilized for detecting vehicle rollover. A delay time selecting system or arrangement is used for selecting a shorter delay time of delay times of two required lengths when vehicle rollover is detected by the rollover detecting sensor and selecting a longer delay time when vehicle rollover is not detected by the rollover detecting sensor. An engine control system or arrangement is provided for reducing the speed of the engine when it is respectively judged by each of these judging systems that the oil pressure detecting sensor has not failed, that the speed of the engine is equal to or above the predetermined engine speed, that the lubricating oil pressure continues to be in a state of being lower than the reference pressure for the predetermined time interval or more, and that a vehicle rollover state continues for or exceeds a selected delay time.
When the engine speed is reduced on the basis of each of the judging systems or arrangements, the engine control system is tasked with stopping drive of the engine or reducing the rotation of the engine to a preset engine speed.
The invention also provides for a vehicle-mounted four cycle engine control device that includes an oil pressure detecting sensor that detects a pressure of lubricating oil circulated under pressure in an engine. An oil pressure detecting sensor failure judging system judges whether or not the oil pressure detecting sensor has failed. An engine speed judging system judges whether or not a speed of the engine is equal to or above a predetermined engine speed. A pressure state judging system judges whether or not the lubricating oil pressure detected by the oil pressure detecting sensor continues to be in a state of being lower than a predetermined reference pressure for a predetermined time interval or more. An engine control system reduces the engine speed when it is respectively judged by each of the judging systems that the oil pressure detecting sensor has not failed, that the engine speed is equal to or above the predetermined engine speed, and that the lubricating oil pressure continues to be in a state of being lower than the reference pressure for a predetermined delay time or more.
The oil pressure detecting sensor failure judging system may operate according to whether or not the oil pressure detecting sensor detects that the lubricating oil pressure is higher than the reference pressure within a required failure judgment time interval after the engine is started and a complete combustion mode has been assumed.
The invention also provides for a vehicle-mounted four cycle engine control device that includes a rollover detecting sensor that detects vehicle rollover. A rollover judging system judges whether or not a vehicle rollover state continues for or exceeds a predetermined time interval. An engine control system reduces an engine speed when it is judged by the rollover judging system that a vehicle rollover state continues for or exceeds the predetermined time interval.
The invention still further provides a vehicle-mounted four cycle engine control device that includes an oil pressure detecting sensor that detects a pressure of lubricating oil circulated under pressure in an engine. An oil pressure detecting sensor failure that judging system judges whether or not the oil pressure detecting sensor has failed. An engine speed judging system judges whether or not the speed of the engine is equal to or above a predetermined engine speed. A pressure state judging system judges whether or not the lubricating oil pressure detected by the oil pressure detecting sensor continues to be in a state of being lower than a predetermined reference pressure for a predetermined time interval or more. A rollover detecting sensor that detects vehicle rollover. A delay time selecting system selects a shorter delay time of two different delay times of different required lengths when vehicle rollover is detected by the rollover detecting sensor and selects a longer delay time when vehicle rollover is not detected by the rollover detecting sensor. An engine control system reduces a speed of the engine when it is respectively judged by each of these judging systems that the oil pressure detecting sensor has not failed, that the speed of the engine is equal to or above the predetermined engine speed, that the lubricating oil pressure continues to be in a state of being lower than the reference pressure for the predetermined time interval or more, and that a vehicle rollover state continues for or exceeds a selected delay time.
When the engine speed is reduced on the basis of each of the judging systems, the engine control system may stop drive of the engine or reduce the rotation of the engine to a preset engine speed.